title: A highly K(+)-selective phenylaza-[18]crown-6-lariat-ether-based fluoroionophore and its application in the sensing of K+ ions with an optical sensor film and in cells.
abstract: Herein, we report the synthesis of two phenylaza-[18]crown-6 lariat ethers with a coumarin fluorophore (1 and 2) and we reveal that compound 1 is an excellent probe for K(+) ions under simulated physiological conditions. The presence of a 2-methoxyethoxy lariat group at the ortho position of the anilino moiety is crucial to the substantially increased stability of compounds 1 and 2 over their lariat-free phenylaza-[18]crown-6 ether analogues. Probe 1 shows a high K(+)/Na(+) selectivity and a 2.5-fold fluorescence enhancement was observed in the presence of 100 mM K(+) ions. A fluorescent membrane sensor, which was prepared by incorporating probe 1 into a hydrogel, showed a fully reversible response, a response time of 150 s, and a signal change of 7.8% per 1 mM K(+) within the range 1-10 mM K(+). The membrane was easily fabricated (only a single sensing layer on a solid polyester support), yet no leaching was observed. Moreover, compound 1 rapidly permeated into cells, was cytocompatible, and was suitable for the fluorescent imaging of K(+) ions on both the extracellular and intracellular levels.
authors.affiliation: Institut für Chemie, Anorganische Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Golm (Germany), Fax: (+49) 331-977-5055; School of Chemistry, University of Sydney, NSW 2006, Sydney (Australia).
authors.forename: Sandra
authors.initials: S
authors.lastname: Ast
authors.forename: Thomas
authors.initials: T
authors.lastname: Schwarze
authors.forename: Holger
authors.initials: H
authors.lastname: Müller
authors.forename: Aleksey
authors.initials: A
authors.lastname: Sukhanov
authors.forename: Stefanie
authors.initials: S
authors.lastname: Michaelis
authors.forename: Joachim
authors.initials: J
authors.lastname: Wegener
authors.forename: Otto S
authors.initials: OS
authors.lastname: Wolfbeis
authors.forename: Thomas
authors.initials: T
authors.lastname: Körzdörfer
authors.forename: Axel
authors.initials: A
authors.lastname: Dürkop
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Holdt
mesh_terms: D043844:Crown Ethers / Q000737:chemistry*; D005453:Fluorescence; D005782:Gels / Q000737:chemistry*; D007476:Ionophores / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D015394:Molecular Structure; D011188:Potassium / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D043844:Crown Ethers; D005782:Gels; D007476:Ionophores; D007477:Ions; D011188:Potassium
keywords: crown compounds; fluorescence; gels; potassium; sensors